Summary: Performance Problem

From: Andreas Höschler <ahoesch_at_smartsoft.de>
Date: Fri Feb 01 2008 - 13:10:33 EST
Dear managers,

thanks to

Casper.Dik@Sun.COM
francisco roque <frisco@blackant.net>
Tim Bradshaw <tfb@tfeb.org>
"Matthew Stier" <Matthew.Stier@us.fujitsu.com>
Markus Mayer <mymaillists@gmx.at>

who suggested to use the following tools to see what is going on.

vmstat -p 10
      memory           page          executable      anonymous      
filesystem
    swap  free  re  mf  fr  de  sr  epi  epo  epf  api  apo  apf  fpi  
fpo  fpf
  18772512 4806232 774 1905 24 0 0  828    0    0    0    0    0  171   
28   24
  18861096 4880280 4072 706 13 0 0   35    0    0    8    0    0  540   
14   13
...

iostat
    tty        md0           md1           md3           md10           
cpu
  tin tout kps tps serv  kps tps serv  kps tps serv  kps tps serv   us 
sy wt id
    0   73 1673 117   27    9   0   39   21   1   34  1221  80   32   12 
  3  0 85


mpstat
CPU minf mjf xcal  intr ithr  csw icsw migr smtx  srw syscl  usr sys  
wt idl
   0  105   1   90    74   17 1431   57  299   73    2  2613   12   3   
0  85
   2  100   0  189   918  395 1434   44  304  116    2  2534   15   3   
0  82
  16  103   1  103    81   21 1467   61  294   85    2  2728   11   3   
0  86
  18   99   3  112   146   83 1663   66  333   86    2  3040   10   4   
0  85

pmap -S 22659
...
-------- ------- -------
total Kb 3284520 3251312

An oracle tool (em) currently - I am still running a test with a 
process currently using 3.2 GB of RAM - gives me

Memory utilization:	72 %

"prstat -s size" make me thinking that only 6 GB or so of the 16 GB 
installed in the machine are used:

    PID USERNAME  SIZE   RSS STATE  PRI NICE      TIME  CPU PROCESS/NLWP
  22659 ahoesch  3208M 3194M cpu18    0    4   1:39:39  25% SmartClient/1
   5950 oracle   1151M 1082M sleep   59    0   0:00:15 0.0% oracle/13
   6793 oracle   1137M 1073M sleep   59    0   0:00:00 0.0% oracle/1
  ...
   6822 oracle   1137M 1077M sleep   59    0   0:00:00 0.0% oracle/1
   5944 oracle   1137M 1073M sleep   59    0   0:00:03 0.0% oracle/1
  27988 nbraun  465M  315M sleep   59    0   0:51:02 0.0% soffice.bin/6
...

I was told that the memory used by oracle is shared so that it actually 
uses 1150 MB only once. So this would be

	3.2 GB 	for my test process
	1 GB 	for oracle
	5 GB 	estimated for all the other processes
	=====================
	9 GB
	
Well, that's actually about 72 %. System performance is fine right now. 
It seems I can't reproduce the problem with my test process. Today a 
user with a 3.4 GB process bogged down the system completely. I will 
need to wait for the next real occurance and then recheck all the 
values.

What numbers in the above stats should I look for first? Looking at 
"prstat -s size" did not get me anywhere. Looking at the output made me 
always think that there should be enough memory left. Is anything fine 
until the second column of "vmstat -p 10" output reaches zero? mpstat 
does not seem to help either, it shows 85% idle all the time. What 
values in iostat output should I have an eye on when the problem 
reoccurs?

Thanks a lot,

   Andreas

> a user process utilizing 2GB - 4GB of memory on a SF 490 (2 x SPARC IV,
> 16 GB) causes serious performance problems for all users. It looks like
> much disk i/o is taking place. The performance problem goes away 1-2
> minutes after killing the user process that consumed the 2GB - 4GB of
> RAM. Since we have 16GB in the machine this should have no effect on
> other users IMHO. No swapping should  be performed since there is more
> than enough physical memory to hold all process data in RAM.
>
> What could be the problem? I heard that Solaris does not like greater
> portion of RAM being occupied by a single process. Is that correct? 
> Why?
>
> Thanks a lot,
>
>    Andreas
> _______________________________________________
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> sunmanagers@sunmanagers.org
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Received on Fri Feb 1 13:11:37 2008

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